Method of packaging



Patented Dec. 28, 1 943 signor to Sylvania Industrial Corporation, Fredericksburg, Va., a. corporation of Virginia Application March 4, 1941, Serial No. 381,630

14 Claims.

The present invention relates to packaging and more particularly it relatesto the packaging of objects in ,pellicleswhich are impermeable to moisture.

more wrappers of material which issubstantially impermeable to moisture. .The wrapping material which has been found most suitable is a pellicle of Cellophane (glycerinated cellulose. hydrate) provided on one or both surfaces. with a moistureproof coating. This material is commonly known throughout the trade as moistureproof Cellophane. Such wrapping of objects is frequently done on wrapping machines which operate at a high speed. The passage of the wrapping material into the machine and the passage of the wrapped articles through the machine frequently disturbs the moistureproof surface of the wrapping material and thereby increases the specific permeability of the wrapper to the passage of water vapor. Even when objects are wrapped by hand the moistureproof surface is frequently so disturbed by rubbing, scratching and the like.

The present invention deals with the re-establishment of the moistureproof characteristics of a pellicle which has been subjected to conditions which have detracted from those characteristics. The moistureproof characteristics may here-established by the present invention to a point where they are substantially equal to or superior to the original characteristics.- It is, therefore, an object of the present invention to provide a method of r'e-establishing the original moistureproof characteristics of a pellicla It is also an object of the present invention to establish moistureproof characteristics in a pel tureproof Wrapper.

It is still another object of the present invention to provide a method of establishing a moismoistureproof surface of moistureproof Cellophane after it has been applied to objects.

.Another object of the present invention is to provide a wrapped object in which the original specific permeability to water vapor of the wrapper has been re-established.

Other objects andadvantages will be apparent to those skilled-in the art from the following detailed description of what are now considered the preferred forms of the invention.

The invention in general comprises wrapping an object in a pellicle which is formed of or coated with a moistureproof composition contain; ing a wax or wax-like substance dispersed throughout the composition and/or over the surface of the composition, and thereafter subjecting the wrapped object for a short time to a relatively high heat to cause the wax or the like to be dissolved in the composition and thereafter cooling the wrapped object to cause the wax to be redeposited throughout the-composition and/or over the surface thereof: The invention further comprises an object so provided with a substantially moistureproof wrapper.

method of protecting an 'object by encasing the object in a pellicle having a surface formed of a composition containing wax and other ingredients tureproof surface on packages provided with a moistureproof wrapper.

It is a further object of the present invention to re-establish the original specific permeability in at least some of which the wax is soluble when molten, exposing the surface to heat for sufficienttime to melt and dissolve the wax in said other ingredients, thereafter cooling the surface to deposit the wax to form a substantially moistureimpermeable surface.

Theinvention accordingly comprises the several steps and relation of one or more such steps with respect to each of the others, and the article possessing the features, properties, and the relation of elements, whichare exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

This application is a continuation in part of applcaton Serial No. 311,473, filed December 29,

1939, and entitled"Surface treating method and article produced thereby.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which: v

The figure is a perspective view of one form of apparatus by which the process of the present invention may be carried out. V The method of the present invention may be utilized in connection with any wrapping or-cov- I 4 More specifically, the invention comprises a" ering material which comprises a pellicle which is rendered moistureproof by being formed of or coated with a preferably heat-fusible composition containing wax or a wax-like substance in solid or hardened form. The pellicle may be in the form of sheet material provided on one or more surfaces with one or more moistureproof coatings containing wax or the pellicle may be in the form of a sheet formed from a composition containing wax dispersed throughout the sheet and/or over the surface. Thus the pellicle may comprise a base sheet formed of non-fibrous cellulosic material, such for example as regenerated cellulose, cellulose esters, cellulose ethers or cel lulose ether-esters; also casein, gelatin, synthetic or natural resins, and similar materials; or fibrous materials, such as glassine paper, paper, felt, woven fabric and the like, provided on one or both surfaces with one or more coatings of a moistureproofing composition or substance which, in its congealed state, is substantially impervious to moisture. Also, the pellicle may comprise a sheet formed of the wax-containing moistureproof composition.

Throughout this specification and the claims, the term wax is to be understood as meaning any well known type of wax, such as, paraffin, spermacetti, ozokerite, ceresin, or the like, aswell as wax-like substances of all types which are used as substitutes for wax, and, of, course, various 'mixtures of waxes and/or wax-like substances.

Because of the ease of procurement and universal usage, the method of the present invention will be descriped as utilized in connection with moistureproof Cellophane (glycerinated cellulose hydrate) provided on one or both surfaces with one or more coatings, of which the exposed coating at least is moistureproof, but it is to be understood that the invention is not so limited. Cellulose hydrate, particularly when in the form of thin sheets, is permeable to moisture. When this material is to be used to encase various objects which are to be articles of commerce, it is frequently desirable and often times necessary to render the cellulose'hydrate moistureproof so as to protect the articles wrapped therein from the ingress of external moisture and the attendant spoilage of the articles. It is also frequently would bring about an undue drying out of the necessary to prevent egress of moisture which wrapped article as in the case of cigarettes, to-

bacco, food products, and the like. By providing the cellulose hydrate sheets on one or both sides with one or moremoistureproof coatings, they may be rendered many times more impermeable to water vapor than similar but uncoat'ed sheets. The moistureproof coatin described in U. S. Patent No. 2,121,023, issued to Ralph T. K. Cornwell on June 21, 1938, has been found particularly well suited for use in accordance with the present invention. The coating described in that patent comprises generally a lacquer base, usually nitrocellulose, a plasticizing resin, a wax and a plasticizer. When this composition is applied to cellulose hydrate in the form of a sheet of regenerated-cellulose, a pellicle is formed which will produce a mostureproof covering' or wrapper or a type which is suitable ,for use in wrapping most of the articles of commerce. Whenever such a coated pellicle which has had its moistureproof characteristics lowered as previously, explained is and when the pellicle is subsequently cooled to the point where the wax becomes insoluble in the gums and resins the wax is redeposited throughout the coating and/or over the surface of the coating, thus reestablishing the moistureproof surface which originally existed on the pelllcle when the coating was first applied to it and before the surface was subjected to scratching, rubbing, abrasion and the like which impaired the moistureproof characteristics of the coating. Also, any wax existing on the surface of the pellicle in sufficient quantity will melt and coalesce over the surface and thus fill any cracks or scratches eventhough the other ingredients of the coating besides the wax do not flow.

The commercial wrapping of articles in moistureproof Cellophane is generally done on wrap ping machinesof various types. These wrapping machines frequently operate at high speeds and during the passage of the moistureproof wrappingmaterial into the machine and the passage of wrapped objects through and out of the machine following wrapping, the rubbing of wrapping material surfaces against parts of the machine scratches and abrades the surfaces and disturbs the moistureproof characteristics of the wrapper to a sufiicient extent to raise its specific permeability to water vapor. This may be due to fracturing of a thin superficial coating of wax disposed over the main coating, or it may be due to the reduction in the thickness of the entire moistureproof coating over certain areas, or to a combination of these results. Likewise, during the hand wrapping of articles, the wrapperis fre quently scratched by the fingernails of the operator or struck against other objects and scarred or scraped so as to impair its moistureproofness.

When a wrapper is so damaged, its moistureproof characteristics may be restored to original conditions and even actually improved thereover by subjecting the wrapped article to a relatively high temperature for a short period as previously described. The intensity of the heat will vary in accordance with the period during which the package is subjected thereto. The heat should be of sufficient intensity in any case to bring about a rapid melting of the wax without causing the entire coating to flow or adversely afiectingthe contents of the package.

Although the invention is not so limited, it is highly advantageous to utilize heat which is produced primarily by radiation since, in this manner, the surface of the wrapper can be rapidly subjected to heat ofsufllcient intensity to melt solvent ingredients contained within the coating I8 raised to a sufficiently high temperature to melt the wax without materially heating the contents or article encased in the wrapper, or even heating the base sheet of the pellicle to any extent, and

actual contact between the heating elements and the pellicle is avoided. In this manner, seals which have. been made in the wrapper as by heatsealing, -that is fusing adjacent surfaces of overlapped areas of the wrapper together by the application of heat and pressure, are not loosened or even weakened by the applicationof heat in accordance with the present invention. Other types of seals are, of course, also not affected. Also, the heating takes place so rapidly that cooling occurs almost instantaneously following the removal of the package from the heated area and the surface of the wrapper is not thereby rendered tacky and subject to adhesion to parts of the machine or other wrapped articles. If desired, the heat may be applied to the wrapped article by any well known type of convection or conduction heater-or a combination of either one or both of these types with radiation heaters may be used. I I

The heat for bringing about melting of the wax is preferably supplied to substantially the entire exterior surface of each wrapped article at one time. One form of apparatus for so applying heat to the surfaces of wrapped objects is illustrated in the accompanying drawing and comprises a suitable housing In which may be formed of any desired material but is preferably formed of some well .known type of heat-resistant material such asasbestos or an asbestos-cement composition. The housing I!) is preferably formed on, or as a part of, or is positioned as close to the wrapping machine as possible to conserve space, but may be positioned at any desired point relative to the wrapping machine.

is meant the number of grams of water which will pass through a one square meter area of a coated pellicle in24 hours. Thus it can be seen that wrapping material which was originally capable of properly protecting the objects or materials wrapped within it, after being subjected to normal wrapping operations was entirely untions have had on moistureproof pellicle has re- For example, in the case where wrapped objects are handled several times incidental to being stored, or as a final precautionary measure just prior to the shipment of the wrapped articles, the housing In may be so positioned as to have the articles passed therethrough as a last step in the storing or shipping procedure.

The housing. Iii is provided with electrically energized resistance heaters l2, preferably dissulted in the deterioration of products wrapped in materials which when originally tested were 1 capable of protecting the products under the concharacteristics of the material indicated would posed at definite intervals along the top and used for other purposes besides wrapping and to I also treat moistureproof materials during the course of their original manufacture.

conveyer may comprise a pair of L-rails 18 on which rollers 20 track. The rollers are carried by a link conveyerbelt formed by links 22 having relatively thin bars 24 extending therebetween. The packages [6 rest on the bars 2d ahdin passing through theheater housing iii are subjected to the heat of the heaters [2 over substantially their entire wrapped surfaces in view of the fact that the bars 24 obscure only a small portion of thelower' surfaces of the wrapped packages.

rlnyother type of heating apparatus may be Since certain changes in carrying out the above process, and certain modifications-in the article which embody the inventionmay be made without departing from its scope, it isintended that all matter contained in the above description shali be interpreted as illustrative. and not in a limiting sense.

Having described the invention, what is clalmedis:

i. The method of packaging comprising encas ing an object in a pellicle formed of nonfibrous cellulosic material having a heat-fusible coating on and near the surface, without causing flow of the remainder of the coating, toform a substantially moisture-impervious surface over the ex- I terior of the pellicle.

trolled so as to' produce rapid melting of the wax followed by a redeposition of the wax throughout the coating and/or over the coating surface.

The present invention makes it possible to rapidly and economically re-establish the original moistureproof characteristics of wrapping materials with attendant increase in the preservative and/or protective qualities of the wrap.- ping material. For example, it has ,been found that a coated cellulose hydrate wrapping material, which at 80 F. and 30% relative humidity had. a specific permeability to water vaportaken as 1, after being applied toan article by'a conventional type of wrapping machine had under the same conditions of temperature and relative I humidity a specific permeability of 4.5,. Upon being treated with heat in accordance with the present invention the original specific permea- 2.. The process of packaging comprising encas- -,ing an object in a sheet material provided with a heat-fusible coating, thereafter applying heat to the package for a suificient time only to provide superficial fusion; in the coating and thereby cause coalescence on' and near the coating surface without causing flow of the remainder of the coating, to provide a substantially moisture-impermeable surface.

3. The method of packaging comprising wrapping an object in a. sheet of cellulose hydrate provided with a moistureproof heat-fusible coating, thereafter applying heat to the package for a sufficient time only to'cause the said coating to fuse superficially, without flowing in its en-.

tirety,-and coalesce into a substantially moistureheat-fusible material, thereafter flash heating the coating to produce superficial fusion therein,

without causing flowof the entire coa ting,.to

bility of 1 was restored. By specific permeabilityv I produce coalescence of the coating surface to form a substantially moistureproof protective covering for the object.

5. The method of protecting objects comprising encasing an object in a pellicle of nonfib'rous material bearing a coating having a heat'-fusible surface, instantaneously subjecting the surface of the wrapped object to intense heat to produce coalescence of the surface, without causing flow of the entire coating, and'thereby form a substantially moisture-impermeable coating over the material.

6. The method of packaging comprising wrapping an object in a sheet of material provided with a moistureproof coating containing wax, the wrapping operation involving possible abrading or scratching of the said coating, and subjectingthe completely wrapped package to heat for a suiiicient time only to fuse the wax, without flowing the coating, and substantially without heating the object to thereby provide a moistureproof package.

7. The method of moistureprooofing a package comprising an object encased in a pellicle having a coating thereon comprising wax, the encasing operation having involved possible abrading,

scratching or other disruption of the coating surface, comprising subjecting the wrapped package to heat without physically contacting the coating surface by the heat-applying instrumentalities for a suflicient time only to fuse and coalesce the wax into a moistureproof-surface without causing substantial flow of the wax, to thereby overcome the damage to the moistureproof characteristics. of the coating substantially without heating the object encased in the pellicle.

8-. The method of packaging comprising encasing an object in a pellicleformed of non-fibrous 'cellulosio material having a heat-fusible coating thereon comprising wax and other ingradients in at least some of which the wax is soluble when molten, thereafter subjecting the encased object to heat for a sufficient time only to superficially. fuse the coating whereupon the wax melts and dissolves therein, and causes the coating to coalesce on and near the surface without causing flow of the remainder of the coating, and finally cooling the coating to form a substantially moisture-impervious surface over the exterior of the pellicle.

composition at least some of the wax is soluble when molten, thereafter, applying heat to the package for a sufiicient time only to cause the said coating to fuse superficially withoutfiowing in its entirety, whereupon the wax melts, and dissolves therein, thereafter cooling the pellicle to coalesce and deposit the wax to form a substantially moisture-impermeable coating.

11. The method of packaging comprising encasing an object in a pellicle formed of nonfibrous material provided with an external coating of heat-fusible material formed of a composition containing wax and other ingredients, in whichlngredients at least some of the wax is soluble when molten, thereafter flash heating the coating to produce superficial fusion therein without causingfiow of the entire coating and to cause coalescence of the coating surface, thereafter cooling the surface to deposit the wax and form a substantially moistureproof protective covering for the object.

12. The method of protecting objects comprising encasing an object in a pellicle of non-fibrous material bearing a coating having aheat-fusible surface, said coating formed of a composition containing wax and, other ingredients in at least some of which ingredients the wax is soluble when molten, thereafter instantaneously subjecting the surface of the wrapped object to intense wrapped packageto heat for a sufhcient time only to fuse the wax without flowing, whereupon the wax melts and dissolves in said composition, and without substantially heating said object, and thereafter cooling the surface to deposit the wax, thereby providing a moistureproof package.

9. The method of packaging comprising encas- 7 ing an object in a sheet material provided with a heat-fusible coating formed of a composition containing wax and other ingredients, in which composition the wax is soluble when molten, thereafter applying heatto the package for a sufllcient time only to provide superficial fusion in the coating, whereupon the wax melts and dissolves therein, and to cause coalescence on andv near the coating surface without causing flow of the remainder of the coating, and thereafter cooling the surface to precipitate the wax, to provide a sub stantially moisture-impermeable surface.

10. A method of packaging comprising wrapping an object in a sheet of cellulose hydrate provided with a moistureproof heat-fusiblejcoating thereon formed at least in part of a composition containing wax and other ingredients,in which 14, The method of moistureproofing a package comprising an object encased in a pellicle having 1 a coating thereon formed of a composition containing wax and other ingredients, in at least some ofwhich ingredients the wax is soluble when molten, the encasing operation having involved possible abrasion or scratching or other disruption of the coating surface, comprising subjecting vthe'wrapped package to heat without physically contacting the coating surface by the heat-applying instrumentalities for a sufficient time only to fuse the wax into a. moistureproof, surface without causing substantial flow of the wax, to thereby overcome the damage to the moistureproof characteristics of the coating substantially without heating the object encased in he pellicle,

thereafter cooling the surface to precipitate the wax and form a substantially moistureproof surface.

RALPH T. K. CORNWELL.

heat to produce superficial coalescence of the- 

